It was, said Nick Clegg, “something you’d expect to see in Putin’s Russia, rather than a Sheffield suburb”. Council contractors and police had descended on a particularly desirable street in his Hallam constituency under the cover of darkness, “dragged” people out of bed to move their cars and detained peaceful protesters – “all to chop down eight trees”, he wrote in a local paper.

So far five people have been arrested in relation to a long-running and increasingly bitter battle over the fate of Sheffield’s trees, including a 70-year old emeritus professor and a 71-year-old retired teacher, both women. On Thursday two men will become the first of the city’s tree protesters to appear in court, charged under trade union legislation, following a protest on 2 November.

Seeing the wood for the trees in Sheffield | Letters

Read more

One of them, the author and university lecturer Simon Crump, 56, a local Green party member, said he was arrested for protecting a 100-year-old London plane tree on Marden Road in Nether Edge. He said he was locked in a cell for eight hours and that he would have been released sooner but, he claimed, officers could not find the offence he had allegedly committed on the police computer. “It was quite Kafkaesque. I was being imprisoned because they couldn’t work out what to charge me with,” said Crump.

Crump has vowed to plead not guilty at Sheffield magistrates court on Thursday, along with the self-described tree campaigner Calvin Payne. “The way I see it, our case has implications for the right to peaceful protest against anything,” said Crump.

The fight for Sheffield’s trees has its roots in a 25-year private finance initiative (PFI) deal signed by the Labour-run council in 2012, which Amey pledged would “see Sheffield’s roads transformed from some of the worst in the country to the best in the country within the first five years”.

Nick Clegg speaks with members of the public after the tree felling in Rustlings Road, Sheffield. Photograph: Danny Lawson/PA

The council says many of the trees are diseased and that their roots have ruined pavements, making them impassible for wheelchair users and buggies.

But the Save Sheffield’s Trees group argues that Amey works without proper consultation and is motivated by profit rather than any desire to protect the trees. “If they blitz the city’s trees in the first five years of their 25-year contract, they can spend the next 20 years with much lower maintenance costs,” the group argues.

They have formed a sort of arboreal neighbourhood watch scheme to keep tabs on any tree that is suddenly adorned with a “felling notice” by Amey, scrambling a protest group as soon as the men with chainsaws turn up.

When contacted by the Guardian on Monday, Amey passed the request on to the council, which previously said of Amey’s work: “If a tree is damaging or obstructing we will make all reasonable practical attempts to try and retain this tree in situ by applying one or more of over 20 sensitive engineering solutions. If these cannot be applied then the tree will be replaced. All trees that are removed as part of this project will be replaced on a one-for-one basis.”

A dawn raid, dissenters silenced: is this a war on trees? | Patrick Barkham

Read more

But the protesters are not convinced. It is a scrap that threatens the Labour party’s future in the city, according to Jim Lafferty, the chair of the Sheffield Central constituency Labour party. On Friday he wrote to Julie Dore, the council leader, warning her that many local party members had quit over the tree dispute and that many council seats could be lost.

“This is not synthetic outrage by a privileged minority of politically motivated opponents of the Labour party, unaffected by the harsh realities of Tory-imposed cuts. Neither is it a desperate attempt by an environmental lobby to block the essential road improvement schemes being carried out across the city,” wrote Lafferty. “This is a rejection by the grassroots membership of the party.”

So far 4,000 trees have been felled, the campaigners claim, with a further 36,000 still standing — most of which are not under threat, the council insists.

The biggest fight so far has been over eight lime trees which have shaded the well-heeled residents of Rustlings Road opposite Endcliffe Park for more than 100 years. As referenced in Clegg’s piece in the Sheffield Star, a team from Amey turned up at 5am two weeks ago to warn car owners that they should move their vehicles if they did not want them to be crushed by breakfast.

Freda Brayshaw, a retired French teacher, was having none of it. Though warned by police not to approach the trees, she stepped over a barrier of tape and moved towards one trunk. The response was swift: for the first time in her 71 years she found herself under arrest and was put into a police car, along with her friend Jenny Hockey, a professor emeritus of sociology at Sheffield University, and a man.

Currently awaiting a court summons, Brayshaw insists she has no regrets, despite spending eight very cold hours in a police cell. “I am passionate about Sheffield’s trees. This is a very polluted city,” she said. “They are doing a job for free: you can work out the value of these trees in terms of flood defences and countering air pollution. That is why we decided to take non-violent direct action to try to save them.”

Save Sheffield’s Trees claim that PFI contracts are bad for democracy because private companies are not subject to freedom of information laws, “so there’s no scrutiny and no accountability”. Many residents, including Clegg, have tried and failed to get hold of an unredacted version of Amey’s PFI contract with Sheffield city council. “We’ve tried so many times that the council has now deemed our requests to be ‘vexatious’,” claimed Crump.

At the weekend the council finally issued a statement on the Rustlings Road situation.

“We would like to offer an apology to the people of Sheffield who were affected by the way in which we took the trees down on Thursday of last week, and particularly those living on Rustlings Road, who will also receive an apology in the post. We are sorry for the disruption and distress caused by the work starting at 5am,” Bryan Lodge, cabinet member for environment at Sheffield city council, said in a statement.

“As we continue to carry out work as part of the largest investment there has ever been in the city’s street trees, and to protect the city’s 36,000 street trees for generations to come, it is important that we take necessary measures to ensure that we protect the safety of our workforce, and the public. But we know we got it wrong last week with the way the work was started. We have listened and are sorry for the mistakes that we made.”